The goal of this project is to obtain an exhaustive description of neuronal response properties in mammalian retinas, principally by intracellular recordings from such neurons and intracellular dye injection techniques, and to correlate these response properties with the ultra-structurally observed synaptic connections of such neurons. An arterially perfused eyecup preparation of the cat has been developed from which it has proved possible to obtain quantitative information concerning rod and cone input, and receptive field properties of many retinal neurons including cones, horizontal cells, bipolar cells, amacrine cells and ganglion cells. We are continuing to develop arterially perfused eyecup preparations for similar studies in rabbit retina and monkey retina. The latter retinas are expected to share many of the features of the cat retina but provide a richer substrate for a study of the basis for chromatic interactions among different cones. A comparison of similar neuronal populations in different species will likely provide a backdrop for understanding the roles of various retinal neurons in the visual process.